Improvement in dentists chairs



2 Sheets-Sheet 1.. J. B. NEWBROUGH.

DENTISTS CHAIR.

No.170, O12. Patented Nov.16, 1875.

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J. 'B. NEWBROUGH.

Patented Nov.16,'1875.

[IKE Haul" Fig 4 DENTISTS CHAIR.

W-IT "ESSES N PETERS, PHOTD-LITHOGRAPHER, WASHINGTON, D. C.

, are to mount the chair on a firm support, while causes the gearing to bind in the rack, and

I is to regulate the rocking or tipping of the UNITED STATES PATENT Orrron.

JoHN B. NEWBROUGH, OF NEW YORK, N. Y., ASSIGNOB- TO SAMUEL s.

, WHITE, or PHILADELPHIA, PENNSYL ANIA.

IMPROVEMENT I N DENTISTS CHAIRSI Specification forming part of Letters Patent No. 170,0 [2, dated November 16, 1875; application filed April 23, 1875.

To all whom it may concern:

Be it known that l, J oHN B. NEWBROUGH, of thecity, county, and State of New York, have invented certain new and useful Improvements in Dentists" Chairs, of which the following is a specification:

My invention relates to a dentists chair having its seat, back, and head-rest capable of adjustment, to adapt it to the varying circumstances under which it is required to operate.

The objects of the first part of myinvention rendering it capable of free vertical adjustment, of being readily raised and lowered and of being automatically locked at any desired height. These objects are attained by mounting the chair frame or support upon a rack-bar, and providing it with gearing to raise and lower the chair, the parts being so organized that the weight of the chair itself thus prevent the descent of the chair.

The object of the next part of my invention is to regulate the horizontal adjustment or oscillation of the chair, which end I attain in the manner hereinafter specifically set forth.

. The object of the next part of my invention chair backward or forward, which end I attain in the manner hereinafter specifically set forth. I The object of the next part of my invention is to vary the height of the back of the chair relatively to the seat, which end 1 attain in the manner hereinafter specifically set forth. The object of the next part of my invention is to give the head-rest a backward and forward and lateral adjustment, which end I attain by mounting the head-rest on a bar slid ing endwise througha loop-bracket clamped by a set-screw upon a supporting-bar mounted on the adjustable portion of the back of the chair, whereby the mechanism for moving the head-rest backward and forward and sidewise, or of varying its inclination, is controlled by a single set-screw.

Theaccompanying drawings represent all my improvements as embodied in a single chair in the best way now known to me; ob-

viously, however, some of theseimprovements may be used without the others, and inch-airs differing in construction from the one shown in the drawings.

Figure l is a perspective view. Fig. 2 is a central vertical longitudinal section. Fig. 3 is atransverse horizontal section through the chair-back. Fig. at is a vertical longitudinal section through the head-rest, enlarged.

A strong upright or rack-bar, A,;-,is mounted upon a suitable base, B, or it may, if 'preferr'ed, be secured firmly to the floor. A rack, i

a, is secured to or forms part of the upright or supporting-post A. A frame,*0, consisting in this instance of a horizontal arm projecting I ion 0, or by a train of gearing of well-known I construction. I The weight and-leverage of the supporting-frame, which it-will be seen projects wholly in front of or sidewisefrom the- I rack-bar, is such as to lock 'or bind the pinion in the rack, and thus prevent the descent of the supporting-frame without otherfastenings but a ratchet, stop, or pawl may be enn ployed as an additional precaution, although not deemed necessary. I

By the mechanism above described, the chair-supporting frame 0 may readily be adjusted to and held at any desired height.

In order to turn the chair proper horizontally, and to hold it at any desired angle, I mount it in a frame, D, pivoted to the sup-.. porting-frame G by means of a set-screw, d, which, when loosened, permits the chair and frame D to turn on its pivot, and, when tightened, clamp them securely in their adjusted position.

By this construction, it will be seen that the chair may freely be adjustedhorizontally, while supported in any position, from just clear of the floor to the uppermost limit of its vertical adjustment, without interfering with its adjustment on the rack-bar support, as the turning-frame is located in front or to the side ofthe rack-bar and clear of it, instead of being above it or its support, as usual.

The chair proper might be rendered adjustable backward or forward by causing this set-screw d to slide in a longitudinal slot in the supporting-frame, or providing a similar slot in the frame D.

In order to regulate the rocking or 'tipping of the chair, I suspend it from the turningframe D by means of uprights or arms E, on

- which the arms of the chair are pivoted, so as to allow the chair to rock on its pivots e, which are at or above the center of gravity of the person occupying the chair,'t-hus preventing any tendency to tip over.

To hold the chair at any-desired inclination, a link or rack-bar, F, pivoted to the back of the chair, passes down through a hole in the rearwardly-projecting portion of the frame D,-and is held at the desired point by a setscrew, f, or its equivalent fastening.

In order to vary the height of the back of the chair, it is made in sections G G The fixed bottom section G is provided with a guide, g, in which a bar, g, on which the movable section G is secured, slides freely endwise, and is heldat any desired pointby a set-screw, 9

By this mode of construction the back of the chair is strongly braced, and its adjustment controlled by a single set-screw, in-

- stead of the double slides which have heretothe back of the movable section G of the back of the chair, carries a loop-bracket, h, capable of moving both endwise thereon, and of swinging around it. A cross-bar, H, capable of sliding freely endwise and of turning in this bracket, carries a head-rest, I. A single set-screw, H, serves to hold these parts together.

By this mode of construction, it will be seen that the head-rest can be moved backward or forward, as .well as laterally; that one end. can be tipped up higher than the other, and that it can be set at any desired angle relatively to the back of the chair, and that all these adjustments can be effected by releasing a single screw, H.

The frame of the chair, as well as the footrest, may be made jointed, or adjustable, if desired, in well-known ways.

I claim as my invention- 1. The combination of the rack, the chairsupporting frame projecting laterally therefrom, and the pinion mounted on the frame, and meshing with and binding in the rack, these members being constructed and operating substantially as set forth, whereby the weight of the frame automatically looks it at any height to which it may be adjusted.

2. The combination of the rack, the supporting-frame projecting laterally therefrom, the adjustable horizontally-turning frame, mounted on the supporting-frame, and the chair pivoted to uprights on said turningframe, these members being constructed and operating substantially asset forth.

3. The combination of the supportingframe, the horizontally-turning frame, the chair pivoted near the line of its arms to uprights on said turning-frame, and the adjustable link connecting the chair-back with the turningframe, these members being constructed and operating substantially as set forth.

4. The combination, in a dentists chair, of the fixed bottom section of the back, the central guide thereon, the movable back section, its central bar sliding in the guide, and the set-screw for clamping the sliding bar and movable section at any desired elevation, these members being constructed and arranged for joint operation as set forth.

5. The combination,in a dentists chair, substantially as hereinbefore set forth, of a headrest mounted on a cross-bar, a loop-bracket, in which said cross-bar turns and moves endwise, which bracket also turns and moves endwise on its supporting-arm, and a setscrew, which clamps the loopbracket and head-rest firmly upon the supporting-arm in any desired position.

In testimony'whereof I have hereunto subscribed my name.

JOHN B. NEWBROUGH.

Witnesses THOMAS PRUDEN, FRANK KUHN. 

